The present invention relates to an ultrasonic system, the ultrasonic system preferably including a rotary ultrasonic horn, and a method of using the same.
It is known to apply ultrasonic energy to a rotary ultrasonic horn while rotating the horn against a continuously advancing workpiece. U.S. Pat. No. 5,110,403 to Ehlert teaches a rotary ultrasonic horn, ostensibly for applying ultrasonic energy to a workpiece along a continuous line of engagement between the workpiece and the radial, or working, surface of the horn.
Application Ser. No. 08/381,363, attorney docket No. 11,460, filed Jan. 31, 1995, in the names of Rajala et al. and of common assignment herewith, teaches a protuberance extending from the outer working surface of the ultrasonic horn, or the anvil, for applying ultrasonic energy to one or more workpieces at spaced locations.
The art is devoid of apparatus and methods for effecting intermittent or spaced application of ultrasonic energy to one or more workpieces without utilizing a protuberance on the ultrasonic horn or the anvil.
It is an object of the invention to provide a method for processing a workpiece using ultrasonic energy to provide an intermittent change of a condition of the workpiece while maintaining constant the radius of the outer radial surface, free from protuberances.
It is another object to provide an ultrasonic system, including a rotating anvil roll having a first length with a first amount of surface area per unit length at the working outer radial surface and a second length with a lesser amount of surface area per unit length at the working outer radial surface, such that a condition of a workpiece is changed as the workpiece passes through a nip between the rotating anvil roll and the ultrasonic horn.
It is yet another object to provide first and second lengths of an outer radial surface of one of the rotating anvil roll and ultrasonic horn, with lands forming a pattern at the respective outer radial surface, such that the lands have a reduced surface area per unit length whereby the ultrasonic energy generated by the ultrasonic horn changes a condition of a workpiece passing through the nip between the rotating anvil roll and ultrasonic horn.
It is still another object to provide the lands as an "X-Y" pattern at the outer radial surface, the lands preferably extending from an underlying base surface at an inwardly sloped angle of between about 5 degrees and about 25 degrees with respect to a perpendicular angle to the base surface.
It is a further object to provide an ultrasonic horn and rotating anvil roll which intermittently bond, cut, or otherwise change, with ultrasonic energy, a condition of a material passing therebetween, while maintaining the workpiece substantially free from changes in tension caused by surface characteristics of the rotating anvil roll or the ultrasonic horn.